Insulating glass panes of the type commonly used as glazing in windows and doors are normally constructed by sandwiching a spacer frame assembly between sheets of glass, and thereafter bonding the sheets to the spacer frame assembly to form an air-tight seal. While, in the past, finished panels were typically square or rectangular, there has been substantial growth in popularity of finished panels having rounded or radiused corners, rather than sharp angles.
It is well known in the art to provide spacer frame assemblies between sheets of glass which consist of several relatively rigid and usually straight spacer tubes, interconnected by a plurality of corner pieces or corner keys. Typical corner keys are disclosed, for example, in U.S. Pat. No. 2,989,788, issued to Kessler; U.S. Pat. No. 4,530,195, issued to Leopold; and U.S. Pat. No. 4,822,205, issued to Berdan. Such keys may be rigid (Mulligan and Kessler), or flexible (Leopold, Berdan). Flexible keys are typically manufactured from appropriately flexible thermoplastics, and may be provided with a locking or positioning mechanism to insure the creation of a precise angle. See, for example, Leopold, or U.S. Pat. No. 5,048,997, issued to Peterson.
Heretofore, however, flexible corner keys, such as those taught by Leopold and Peterson, have been unacceptable in many installations, insofar as they tend to create a relatively sharp corner.
Along with the growth and popularity of finished panels having rounded or radiused corners, there have been an increased need for corner keys suitably, adapted to the useful and aesthetically pleasing large radiuses.